One of the most useful techniques in photography is called bracketing – in other words, taking multiple photos of the same subject with different camera settings. Commonly, bracketing is about changing your exposure: one photo at the meter’s recommendation, plus one under and one over. But exposure isn’t the only variable at play here. Below, this article explains everything you need to know about bracketing, including how and when to use it to take the best possible photos.
Why Would Anyone Bracket Photos?
Bracketing means that you capture a sequence of photos while changing your camera settings from shot to shot. This means you end up with two or more photos of the same scene, with only a couple differences in each one.
Regarding the example of exposure – the most common type of bracketing in photography – you’ll usually end up with one photo that is too dark, one that is too bright, and one with an accurate exposure. But you can also bracket settings like focus distance, resulting in one photo that is front-focused, one that is back-focused, and one that is accurate.
At the face of things, bracketing just takes up space and wastes time. Especially if you know exactly what settings you need for an image, why bother bracketing? But there are two very real reasons why bracketing is so helpful in photography.
1. Playing It Safe
First, no matter how sure you are of your camera settings, you might be wrong. The three exposures you planned – one overexposed, one underexposed, and one correct – won’t always turn out that way. Instead, you might capture one underexposed photo, one drastically underexposed photo, and one that is correct.
No one is a perfect judge of exposure in the field, especially in high-contrast light or other tricky conditions. Bracketing, then, is a way to take precautions against common errors you might make. Especially for important images, it’s a low-risk, high-reward technique.
Personally, in my landscape photography, I sometimes find it tricky to expose small highlights in the sky without blowing them out (i.e., making them completely white). Normally, what I think of as a “cautious exposure” might still be overexposed. Bracketing has saved my photos in more than a few such cases. For example, here are three unedited bracketed images:
Of the images above, it is actually the darkest one on the left which is closest to an “ideal” exposure. The other two have extensive areas of blown highlights in the clouds, and fully recovering them is impossible. Click to see larger.
2. Merging Photos
Other times, bracketing is the only way to capture the photo you have in mind (in combination with some post-processing later). For example, if you’re shooting an ultra-high-contrast scene, one photo just might not cut it. A single “normal” exposure will lead to highlights that are too bright, while also resulting in dark, noisy shadows.
Although you can sometimes get around this sort of problem with a graduated ND filter, the more practical option in many cases is to do things digitally. Take an underexposed photo so the highlights look good, plus an overexposed photo so the shadows are right. Then, combine the best parts of each photo into an HDR or luminosity blend.
You can go beyond a two-photo blend, of course. Three photos are most common. Personally, I don’t like blending exposures with more than 2/3 stop of exposure between them, or, at most, 1 stop – because otherwise the transition areas can start to look grainy and odd. So, when I know I need an HDR, I’m generally shooting three-photo brackets, sometimes more. The images in the previous section make a good HDR when blended together. Same with the photo below, taken of a fairly high-contrast scene. This is a three-image blend:
NIKON D800E + 20mm f/1.8 @ 20mm, ISO 100, 6 seconds, f/16.0
Again, though, blending a set of bracketed images goes beyond just exposure. We already have a detailed article on focus stacking, another technique that is very relevant to this topic. Specifically, when you take several shots focused at different points, you can combine the best parts of each one into a pin-sharp result. This also counts as bracketing, since it involves several photos of the same scene while varying camera settings from one to the next. It’s something a lot of landscape and macro photographers use to artificially extend their depth of field.
How to Do Exposure Bracketing
The actual process of exposure bracketing is easy. In any semi-automatic mode, just change your exposure compensation from shot to shot. In manual mode, just change any of the “big three” settings manually: aperture, shutter speed, or ISO. However, as I’ll cover in a moment, you should pick carefully which to adjust if you want the best results.
Also, almost every camera today lets you set up automatic bracketing with an option in the menu. When enabled, your camera automatically changes settings from shot to shot rather than making you change it manually. Some cameras only allow exposure bracketing, while others have bracketing options for JPEG settings, white balance, and other camera settings. Although bracketing is found in the menu of most cameras today, you can usually assign a custom button to access it quicker. Some cameras even have a specific bracketing button, although that is less common today:
Bracketing button on the Nikon D7000
Either way, I recommend going the camera’s built-in bracketing route. Critically, it means you can take a bracketed set of photos faster than doing things manually. If your camera is set to high-speed continuous shooting, for example, you might be able to capture a five-image HDR in less than a second. If anything in your photo is moving, this makes it much more likely that your blend is successful later.
Which Exposure Setting Should You Bracket?
A moment ago, I mentioned that it is important to choose your bracketing setting carefully. Even though you can bracket shutter speed, aperture, and ISO just as easily as one another, you’ll be happier with some results more than others.
Aperture: First, aperture is often the worst of the three settings you can bracket, since it affects depth of field in addition to just exposure. If you try to create an HDR from f/4 to f/5.6 to f/8, the result may look very odd (with unnatural transitions from blurry to sharp regions). A five-image bracket would be worse. Many of the individual photos will no longer have the right depth of field, making them unusable. Imagine how annoying it would be for your only good exposure of a scene to have the wrong depth of field…
ISO: Second, ISO also is not ideal to adjust, since your shots at each ISO will have different levels of image quality. An HDR from ISO 400, 800, and 1600 shots is not going to give you much improvement over a single ISO 400 image with shadow recovery in post. Don’t get me wrong – bracketing is still a good idea at higher ISOs if you want to play it safe and avoid blowing out the highlights in tricky situations. Just keep in mind that an HDR from different ISO shots won’t be vastly better than a single image in quality.
Shutter Speed: Third is shutter speed – the exposure setting you should always adjust first if possible. Especially if you’re shooting from a tripod, and your subject isn’t moving, it’s a no-brainer; shutter speed is the way to go. However, in scenes with quickly-moving subjects and the potential for motion blur, you might not have the flexibility to bracket shutter speed. In those cases, ISO is often the better choice. I still wouldn’t bracket aperture – although perhaps you can use a wider aperture for all your photos so you no longer have a problem bracketing shutter speed.
As a side note, I recommend using either manual or aperture-priority mode (with Auto ISO turned off) for bracketing exposure. Otherwise, you might end up bracketing aperture or ISO unintentionally, when you intended to adjust shutter speed instead.
How to Do Focus Bracketing
Focus bracketing is easier than exposure bracketing, since there is only one setting under consideration: focus distance. Here, your goal usually involves focus stacking the images in post-processing later. However, in some cases – like a group photo where you need everyone sharp, but don’t know exactly where to focus for the best result – there is still an element of playing it safe.
Focus bracketing works best when you overlap your depth of field from shot to shot. If your “steps” are too wide, you might end up with a final photo that looks very odd: sharp, blurry, sharp, blurry, sharp, and so on from the front of the frame to the back.
When you’re bracketing focus manually, I recommend taking photos with smaller focus increments than you would expect. If you have time, magnify live view and then review each photo afterwards to double check that the transitions are smooth. However, be aware that previews on the camera’s rear LCD look very different than full-size images on a large, high-resolution monitor. For optimal results, you might need to be even more cautious than you’d expect.
A lot of cameras today have a built-in focus stack feature to simplify this process. Just focus on your nearest subject, tell the camera how many photos to take, and select a step size. Again, I recommend selecting a lower step size than you might expect, just to be safe. It’s also a good idea to test this feature ahead of time so you know how to use it correctly when the photo really matters.
30 image focus stack, automated on the Nikon Z7
NIKON Z7 + NIKKOR 70-200mm f/4 @ 200mm, ISO 64, 1/20, f/10.0
Other Types of Bracketing
In theory, bracketing can refer to pretty much any variable in photography. You can bracket white balance, JPEG settings, long exposure noise reduction, flash settings, focal length, and much more.
For example, if you don’t know exactly what depth of field you want, it might be worth bracketing your aperture just in case (compensating with shutter speed so your overall exposure doesn’t change). Or, for Milky Way photography, you may take photos at different ISO and shutter speed settings to get the best combination of noise performance and minimal star trails.
Personally, I even consider composition to be a part of bracketing, and same with other variables like the time of day when you take a picture. Sometimes, you’ll end up taking two or three photos from the same tripod position, but thirty minutes apart – one at night, one at blue hour, and one at sunrise. (Click on the three images below for one such example.) Some photographers may not consider this to be “bracketing” in the true sense, but I don’t really care what you call it. After all, your goal – to hedge your bets and improve the odds of getting a successful image – remains the same in either case.
When You Should and Shouldn’t Bracket
As useful as bracketing is, it won’t always be worth doing in the field. Exposure bracketing, especially, doesn’t help if you already know exactly what exposure you want. It just fills up your memory card faster. On top of that, bracketing can take up extra time if you’re trying to work quickly, even if you use the camera’s built-in bracketing feature. (After all, if your metered exposure is a 15 second shutter speed, bracketing one stop over will make you wait another 30 seconds per shot.)
The biggest reason to avoid bracketing, though, is when you’re photographing action. For example, say that you’re a wildlife photographer with a bird flying toward your camera. You probably have a good “safe” exposure in mind that is unlikely to blow out any details. Bracketing, in this case, means that you’re missing two of every three exposures in your sequence – including, quite possibly, the best moment of action – just to reduce the already small chance that your safe exposure is incorrect. That’s not a tradeoff I’d make.
NIKON D800E + 105mm f/2.8 @ 105mm, ISO 800, 1/800, f/2.8
Bracketing here wouldn’t have been a good idea, since it would have increased my odds of a poor exposure while the bird was at the best location.
Instead, I recommend leave bracketing to situations that are not so fast-paced. Architectural photography, landscape photography, studio photography, and so on – these are all good times to bracket your photos. Also, in some time-sensitive cases, you may wish to enable bracketing after you’ve already captured what you think is the right shot. For example, once you’ve taken the wildlife photo you want, it’s not a bad idea to enable bracketing and keep taking pictures just in case.
Summary
Although it is not a tool you should use for every photo, bracketing has the potential to improve your number of keepers significantly under the right conditions. As a landscape photographer, I bracket my exposures very often in tricky conditions, whether to play it safe or to create an HDR later. I also bracket focus for certain images, and – if you’ll count it as bracketing – I vary my composition and shoot at different times of day for a huge number of important photos.
Bracketing is no substitute for learning how to take good pictures the first time around. But no one gets the perfect exposure every time, and it’s worth a small bit of effort to improve your chances of a good result. Hopefully, if you rarely or never used bracketing before reading this article, you now have a good idea of when to try it for your own photography.
#Exposure #HDRPhotography #HDR #ExposureCompensation #Bracketing
